Pipe cutter



April 24, 1962 s. F. DE CORDOVA PIPE CUTTER 2 Sheets-Sheet 1 Filed June 29, 1959 .m m w.@ HWWA J w 2 i m8 J April 24, 1962 Filed June 29, 1959 1IZZZZZW mm B S. F. DE CORDOVA PIPE CUTTER 2 Sheets-Sheet 2 INVENTOR. .Zie Cora 0 l/a ATTORNEY;

. section of pipe.

' Patented Apr. 24, 1962 3,031,015 PIPE CUTTER Sam F. de Cordova, Box 494, Morgan City, La. Filed June 29, 1959, Ser. No. 823,692 7 Claims. (Cl. 16655.6)

This invention relates to pipe cutters, and more particularly to devices to be used in a well which wash over a section of stuck pipe, cut free a portion of the section of stuck pipe, and retrieve the freed section from the well bore, all in one run of the tool.

Drill pipe sometimes becomes stuck in a well due to cave-ins of the wall of the well, and the like, and cannot be withdrawn from the well bore. When this occurs, the drill pipe is usually parted immediately above the stuck section of pipe and efforts are made to remove the stuck One common method is to wash over the stuck pipe with an annular cutting tool which surrounds the pipe. After a length of the stuck pipe has been washed over and freed in the well, the wash-over tool may be withdrawn and a cutting tool run in the well to cut free and retrieve the freed section of the stuck pipe.

Due to the time involved in running pipe in the well, the wash over, cutting and retrieving operation is desirably carried out by a single tool, and many tools have been proposed for this purpose.

One of the problems encountered is that the cut is not always completed, and it is necessary to release the stuck pipe or fish and move the tool to a new position and attempt to make a new cut. It also may be desirable to retrieve the tool from the hole in the case of broke cutting knives or mal-function of the tool.

It is desirable to anchor the tool to the pipe to gain purchase in driving the knives into the pipe, and considerable difficulty is encountered in releasing the tool from the pipe when desired.

It is an object of this invention to provide an outside pipe cutter which may be utilized to wash over a stuck pipe, out free a section of the stuck pipe, and retrieve the stuck pipe, all in a single run of the tool.

Another object is to provide an outside cutting tool in which the tool may be completely released from the stuck fish at any time.

Another object is to provide an outside cutting tool which may be released from a stuck fish and thereafter moved to a new section of the fish and a new cut begun without removing the tool from the well.

Another object is to provide an outside pipe cutter in which the means for urging the cutting knives into engagement with the pipe is automatically moved into nonoperative position upon release of the tool from a pipe to permit disengagement of the knives from the pipe to be cut.

Other objects, features and advantages of the invention will be apparent from the specification, the drawings" and the claims.

In the drawings, wherein there is shown an illustrative embodiment of this invention, and wherein like reference numerals indicated like parts:

FIGURE 1 is a view partially in vertical elevation and partially in vertical cross-section through a pipe-cutting tool constructed in accordance with this invention, and

. shown over a drill pipe;

FIGURE 2 is a view in vertical cross-section through the tool of FIGURE 1 and illustrating the position of the parts at the time the tool is initially anchored to a pipe;

FIGURE 3 is a view similar to FIGURE 2 showing the tool in pipe-cutting position;

FIGURE 4 is a view along the line 44 of FIGURE 1; and,

FIGURE 5 is a view along the line 55 of FIGURE 1.

The drill pipe 10 will be stuck in a well bore (not shown). In the conventional manner, the outside pipe cutter will be rotated and moved downwardly over the pipe 10 to cut away the annulus of material binding the pipe to the well bore. A suitable annular bit 11 is shown at the bottom of the tool for performing this operation.

After a suitable section of pipe has been washed over, it is desirable to anchor the tool to the pipe to permit upward movement of the wash-over pipe to urge the cutting knives 12 into the pipe. For this purpose, the pipeanchoring means 13 is provided. This means includes a slip bowl 14 which co-acts with a plurality of slips 15 to move the slips inwardly and anchor the pipe cutter to the pipe. Preferably, the slips engage the lower shoulder of a collar 16 on the pipe and prevent upward movement of the anchoring assembly.

It is desired to prevent operation of the anchoring assembly 13 before the operator is ready to out free a section of the stuck pipe, and for this purpose means are provided to maintain the slips 15 in a position above the bowl 14 when the bowl is in its uppermost position. This means may be provided by the jump-thread arrangement shown, which includes interior threads 17 in the outer pipe 18 and threads 19 carried on a yieldable member 20. The yieldable member 20 is mounted on the slip carrier 21. The threads 17 and 19 are buttress-type threads and prevent downward movement of the slip carrier relative to the outer pipe 18. However, upon upward movement of the outer pipe 18 by the wash-over string 22 and simultaneous right-hand rotation, the slip carrier 21 may be threaded through the outer pipe. To provide for relative rotation between the outer pipe 18 and the slip carrier a suitable drag arrangement is provided to hold the slip carrier against rotation. The drag arrangement may be provided by the knuckle arm arrangement illustrated. This arrangement includes an arm 23 pivoted to the slip carrier at 24, and an arm 25 pivoted to arm 23 at 26. Arm 25 is also pivoted to the sliding annulus 27 at 28. A compression spring 29 is compressed between annulus 27 and a flange 31 on the slip carrier 21. Thus, the knuckle arms 23 and 25 will always be urged into frictional engagement with the pipe 16 by spring 29 and provide suflicient drag to permit the slip 15 to be released upon simultaneous upward and rotative movement of the wash-over string 22.

By reference to FIGURE 4 it will be noted that there are three arms 20 spaced symmetrically about the cutting tool and also three drag knuckle joints are provided. As each of these structures is identical, only one has been explained herein.

After the slip carrier has been released in the manner explained, the drag links continue to frictionally engage the pipe 10 and upward movement of the outer The slip bowl 14 is carried by an inner sleeve 32 which is mounted in the outer sleeve 18 for telescoping movement and is splined against rotation relative thereto by splines 33. The sleeve 32 carries a plurality of cutting knives 12 which are urged toward pipe by a knife actuator 34. The knife actuator 34 has an upwardly extending wedge member 34a behind each knife 12, and, upon movement of the actuator and sleeve toward each other, these members 34a move the knives inwardly to pipe-cutting position. The knife actuator 34 is urged toward sleeve 32 by a compression spring 35 which is compressed between the knife actuator and a shoulder 36 on the lower end of the outer pipe 18. As best shown in FIGURE 3, spring 35 is compressed by upward movement of the outer pipe relative to the sleeve 32. As the sleeve 32 is connected to the slip-bowl 14 by ball-bearing assembly 37, the inner sleeve cannot move upwardly with the outer pipe.

In order that a predetermined force may be applied to the knife actuator by spring 35, it is preferred to provide stop means limiting upward movement of the outer pipe 18 relative to the inner sleeve 32. This may be provided in any desired manner, and when this stop is engaged the increased tension on the wash-over pipe 22 will advise the operator that the tool is ready for cutting operation. Of course, as the knife moves inwardly with penetration into the pipe 10, the spring 35 will expand slightly and maintain a knife-expanding pressure behind the cutting knife.

While the means for limiting upward movement of the outer pipe relative to the sleeve 32 might be provided'by any desired stop, it is preferably provided by the convolutions of spring 38 moving into abutment with each other.

It is sometimes desirable to release the tool from the -pipe before a cut has been completed, and in this case the knives should be retracted from engagement with the pipe 10. For this purpose, the spring 38 urges the inner sleeve 32 upwardly relative to outer pipe 18. Thus, upon lowering of outer pipe 18 the inner sleeve will re- -main stationary until the compression is removed from spring 38. It is noted that the inner sleeve 32 is provided with an outer lower flange 39 which engages spring 38 when in its uppermost position to limit further expansion of spring 38. At this time, the upper end 41 of slip-bowl 14 will contact downwardly facing shoulder 42 in the outer pipe 18 and further downward movement -of the outer pipe will move the slip bowl from behind the slips 15. As the slips are mounted on spring arms 15a, they will return to fully retracted position as shown in FIGURE 1.

From the structure thus far described, it will be apparent that the anchor can be released and upon further downward movement of the outer pipe 18 relative to slip carrier 21, which is held against movement by the knuckle arms, the threads 17 in the outer pipe will jump the threads 19 carried by yieldable arm 2-0. This will render the anchoring mechanism ineffective so long as the pipe is not thereafter rotated.

Inasmuch as a wedge action is present between the knives and knife-actuators, it would be possible for the actuators to hang up in a position which wound bind the knives in the cut in the pipe 10. To avoid any possibility of this occurring, a stop is provided in the outer pipe 18 which engages the knife-actuator before the spring 38 moves into fully expanded position and in and if for any reason the actuator does not retract freely, the stop 33a forces the knife-actuator from behind the several knives. As shown in FIGURE 5, three splines 33 are spaced symmetrically about the tool and the knife-actuator will be engaged at three symmetrically spaced positions to retract it from behind the knives. Each knife is provided with a return spring 44 which urges each knife radially outwardly away from the pipe 10 and moves the several knives positively to retracted position upon withdrawal of the knife-actuator 34.

In operation, the tool is run in with the parts in the posture illustrated in FIGURE 1. As the weight of the tool will be exerted on the annular bit 11 through the cutting tool, a downward force will be constantly exerted during rotation which will prevent release of the jumpthread mechanism. Upon reaching a desired elevation, the operator picks up slightly on the pipe 22 while continuing rotation, and as the knuckle arms 23 and 25 are dragging against the pipe 10, the slip carrier 21 will be forced downwardly until the threads 17 and 19 are disengaged. Thereafter, further upward movement of the wash-over string will move the outer pipe upwardly relative to the frictionally held slip carrier 21 until the bowl 14 forces the slips 15 into engagement with the pipe. Further upward movement of the wash-over pipe 22 will move the slips 15 into engagement with the next collar 16 located thereabove. At this time further upward movement of the wash-over pipe 22 will compress spring 38 and simultaneously will compress spring 35. Upon the convolutions of spring 38 moving into abutment with each other, further upward movement of the wash-over pipe will be resisted, and the operator will know that the tool is ready for cutting. While the spring 38 was being compressed, the compression of spring 35 was moving the knife-actuator 34 behind knives 12. This movement of the parts while the springs are compressed is illustrated by the difference between FIGURE 2 and FIGURE 3. It is noted that the spline 33 moves out of engagement with the knife-actuator 34 and permits spring 35 to force the knife-actuator behind the knives.

At this time the tool may be rotated to cut the pipe 10 in two. Upon severing of the section of pipe, the washover string 22 may be withdrawn with the severed section of pipe supported upon the slip 15.

If for some reason it is impossible to complete the cut, and it is desirable to release the tool, the operator lowers string 22 and merely by straight downward movement the tool is completely released from the pipe and all parts placed in inoperative position. As the outer pipe 18 moves downwardly, the spring 38 expands to support the knife carrier in its upper telescoped position. As the spring 38 reaches fully expanded position, the shoulder 42 engages the upper end of the bowl 14 and drives the bowl from behind the slips. Meanwhile, the spring 35 has been expanded to remove the force urging knifeexpander 34 upwardly, and splines 33 engage the knifeactuator to move it downwardly relative to the knives and release the knives before spring 38 has been completely expanded. As the knife-actuator moves from behind the knives, the individual springs 44 retract the knife into non-cutting position. The threads 17 move over threads 19 and hold the slip carrier in its upper position so that the slips will be inactive upon a later upward movement of the wash-over string.

The pipe cutter is now free from the pipe and may be moved to another position and operated in the manner previously explained to make a new cut, or the tool may be withdrawn from the hole completely.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof and various changes in the size, shape and and materials, as well as in the details of the illustrated construction, may be made within the scope of the appended claims without departing from the spirit of the invention.

What is claimed is:

1. An outside pipe cutter comprising, an outer pipe adapted to be carried by a washover pipe string, an inner sleeve splined and telescoped in the pipe, means urging the sleeve upwardly in the pipe, anchoring means including slips and a bowl for contracting the slips, said bowl rotatably carried by the inner sleeve, yieldable means carried by one of the slips and outer pipe, jump thread means on said yieldable means and the other of said slips and pipe, said jump thread means releasably supporting the slips in the outer pipe above the bowl when the bowl is in its uppermost position, said jump thread means permitting release and downward movement of the slips into engagement with the bowl upon upward movement and rotation of said pipe and re-engagement of the pipe and slips upon downward movement of the pipe relative to the slips, cutting knives carried by the inner sleeve, knife actuator means for urging the cutting knives into a pipe to be cut, resilient means carried by the outer pipe urging the actuator means toward engagement with the knives, said inner sleeve when secured to the pipe by the anchoring means holding the knives against longitudinal movement along the pipe to be cut whereby upon upward movement of the outer pipe the actuator means urges the knives into cutting position.

2. An outside pipe cutter comprising, an outer pipe adapted to be carried by a washover pipe string, an inner sleeve splined and telescoped in the pipe, means urging the sleeve upwardly in the pipe, anchoring means including slips and a bow-l for contracting the slips, said bowl rotatably carried by the inner sleeve, yieldable means carried by one of the slips and outer pipe, jump thread means on said yieldable means and the other of said slips and pipe, said jump thread means releasably supporting the slips in the outer pipe above the bowl when the bowl is in its uppermost position, said jump thread means permitting release and downward movement of the slips into engagement with the bowl upon upward movement and rotation of said pipe and re-engagement of the pipe and slips upon downward movement of the pipe relative to the slips, cutting knives carried by the inner sleeve, knife actuator means for urging the cutting knives into a pipe to be cut, resilient means carried by the outer pipe urging the actuator means toward engagement with the knives, a stop preventing contact between the knives and actuator means when the inner sleeve is in its uppermost position, said inner sleeve when secured to the pipe by the anchoring means holding the knives against longitudinal movement along the pipe to be cut whereby upon upward movement of the outer pipe the actuator means urges the knives into cutting position.

3. An outside pipe cutter comprising, an outer pipe adapted to be carried by a washover pipe string, an inner sleeve splined and telescoped in the pipe, means urging the sleeve upwardly in the pipe, means limiting downward movement of the sleeve in the pipe, anchoring means including slips and a bowl for contracting the slips, said bowl rotatably carried by the inner sleeve, yieldable means carried by one of the slips and outer pipe, jump thread means on said yieldable means and the other of said slips and pipe, said jump thread means releasably supporting the slips in the outer pipe above the bowl when the bowl is in its uppermost position, said jump thread means permitting release and downward movement of the slips into engagement with the bowl upon upward movement and rotation of said pipe and re-engagement of the pipe and slips upon downward movement of the pipe relative to the slips, cutting knives carried by the inner sleeve, knife actuator means for urging the cutting knives into a pipe to be out, resilient means carried by the outer pipe urging the actuator means toward engagement with the knives, said inner sleeve when secured to the pipe by the anchoring means holding the knives against longitudinal movement along the pipe to be cut whereby upon upward 6 movement of the outer pipe the actuator means urges the knives into cutting position.

4. An outside pipe cutter comprising, an outer pipe adapted to be carried by a washover pipe string, an inner sleeve splined and telescoped in the pipe, means urging the sleeve upwardly in the pipe, means limiting downward movement of the sleeve in the pipe, anchoring means including slips and a bowl for contracting the slips, said bowl rotatably carried by the inner sleeve, yieldable means carried by one of the slips and outer pipe, jump thread means on said yieldable means and the other of said slips and pipe, said jump thread means releasably supporting the slips in the outer pipe above the bowl when the bowl is in its uppermost position, said jump thread means permitting release and downward movement of the slips into engagement with the bowl upon upward movement and rotation of said pipe and re-engagement of the pipe and slips upon downward movement of the pipe relative to the slips, cutting knives carried by the inner sleeve, knife actuator means for urging the cutting knives into a pipe to be cut, resilient means carried by the outer pipe urging the actuator means toward engagement with the knives, a stop preventing contact between the knives and actuator means when the inner sleeve is in its uppermost position, said inner sleeve when secured to the pipe by the anchoring means holding the knives against longitudinal movement along the pipe to be cut whereby upon upward movement of the outer pipe the actuator means urges the knives into cutting position.

5. An outside pipe cutter comprising, an outer pipe adapted to be carried by a washover pipe string, an inner sleeve splined and telescoped in the pipe, a spring urging the sleeve upwardly in the pipe, said spring when collapsed limiting upward movement of the pipe relative to the sleeve, anchoring means including slips and a bowl for contracting the slips, said bowl rotatably carried by the inner sleeve, yieldable means carried by one of the slips and outer pipe, jump thread means on said yieldable means and the other of said slips and pipe, said jump thread means releasably supporting the slips in the outer pipe above the bowl when the bowl is in its uppermost position, said jump thread means permitting release and downward movement of the slips into engagement with the bowl upon upward movement and rotation of said pipe and re-engagement of the pipe and slips upon downward movement of the pipe relative to the slips, cutting knives carried by the inner sleeve, knife actuator means for urging the cutting knives into a pipe to be cut, resilient means carried by the outer pipe urging the actuator means toward engagement with the knives, said inner sleeve when secured to the pipe by the anchoring means holding the knives against longitudinal movement along the pipe to be cut whereby upon upward movement of the outer pipe the actuator means urges the knives into cutting position.

6. An outside pipe cutter comprising, an outer pipe adapted to be carried by a washover pipe string, an inner sleeve splined and telescoped in the pipe, a spring urging the sleeve upwardly in the pipe, said spring when collapsed limiting upward movement of the pipe relative to the sleeve, anchoring means including slips and a bowl for contracting the slips, said bowl rotatably carried by the inner sleeve, yieldable means carried by one of the slips and outer pipe, jump thread means on said yieldable means and the other of said slips and pipe, said jump thread means releasably supporting the slips in the outer pipe above the bowl when the bowl is in its uppermost position, said jump thread means permitting release and downward movement of the slips into engagement with the bowl upon upward movement and rotation of said pipe and re-engagement of the pipe and slips upon downward movement of the pipe relative to the slips, cutting knives carried by the inner sleeve, knife actuator means for urging the cutting knives into a pipe to be cut, resilient 7 8 means carried by the outer pipe urging the actuator means f pr vi e for urging the knives Into non-cuttlng P toward engagement with the knives, a stop preventing 11011 t ll scontact between the knives and actuator means when the inner sleeve is in its uppermost position, said inner sleeve References Cited m the file of thls patent when secured to the pipe by the anchoring means holding 5 UNITED STATES PATENTS the knives against longitudinal movement along the pipe 1,839, 22 Ventresca J 5, 1932 to be cut whereby upon upward movement of the outer 2,202,985 Ellis June 4, 1940 pipe the actuator means urges the knives into cutting 2,325,104 Brown et a1. July 27, 1943 position. 2,462,230 Smith Feb. 22, 1949 7. The outside pipe cutter of claim 6 wherein means 10 2,572,997 Edwards Oct. 30, 1951 

